Well now, just get right started, why don't ya!
Dig the one piece mount, muffler and masking.
The muffler profile is so "stock" looking, just paint it flat black when you are done to compete the appearance. Might want some extra heat reflector on the side panel to keep it from melting, its gonna get a bit hot under there.

Probably want a shield where turbine body protrudes too, otherwise you will get the classic KTM dirtbike pants/boot burn.

Thinking of moving heat, would ceramic coating the inners of your muffler box and core help lower temps around/outside the box?